The District of Columbia (D.C.) Perinatal Study is a case-control study designed to elucidate the factors associated with the delivery of a low birth weight infant to Black mothers residing in D.C. The study "cases" were low birth weight infants (<2500 grams) born in participating hospitals. "Controls" were selected as the next race-matched normal weight infant (greater than or equal to 2500 grams) delivered at the same hospital. The mothers of the cases and controls were interviewed on the postpartum ward, with data verification obtained through abstraction of medical records. Where possible, prenatal information was verified by using the prenatal information which was attached to the hospital medical record. If the hospital medical record, however, did not contain adequate prenatal information, arrangements were made to abstract this information from private and public physician's offices where care was received. Data collection began February 1, 1984, and continued until January 31, 1985. The data was collected by SRA Technologies, Inc., of Arlington, Virginia. In September 1985 SRA returned the data instruments to NICHD due to an inability to complete the contract. Raw data was returned as well as data entered on two data tapes and disk through the Division of Computer Research and Technology (DCRT). It was necessary to re-key all of the data originally submitted by SRA Technologies. One hundred percent of the data have now been keyed.